Photographic reversal process



June 18, 1935. K. c. D. HICKMAN 2,005,368

PHOTOGRAPHIC 'REVERSAL PROCE$S Filed June 15, 1932 Dry Defielop (remove (lye) Bleach liezmeihallfliulizzuw,

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I (hung- Patented June 18, 1935 UNITED STATES PATENT OFFICE PHOTOGBAPHIO BEVERSAL PROCESS Application June 15, 1932, Serial No. 817,368

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This invention is an improvement in the photographic reversal process of the type in which the second exposure is controlled.

Such a procem and apparatus for carrying it out are disclosed in the patents of John 0. Capstafl, No. 1,460,703, granted July 3, 1923, and No. 1,690,616, granted November 6, 1928.

I have found that the final image may be even more fully controlled ii, prior to the second exposure, the film is passed through a dye bath which stains it during such second exposure, the dye being then removed. Particularly if the exposure is made by light of selected color in the manner disclosed in the patent of J. G. Capstafi, No. 1,690,617, granted November 6, 1928, the contrast or this final image may be controlled to .obtain the desired results.

Reference will be made to the accompanying drawing, the single figure oi. which shows diagrammatically a processing machine of the type more fully shown and described in the above mentioned Patent No. 1,690,616. As shown in this figure, the film F is advanced from a supply roll I over suitable guide rolls or sprockets 2, selected ones of which may be driven, and is thus advanced through a series of tanks indicated as A, B and C respectively, in which the film is developed, bleached and cleared. It then passes througha shallow tray 3 containing an aqueous dye bath, the dye ordinarily selected being a yellow dye, such as tartrazine.

The film is submerged in the dye bath by means oi guide rolls 4 and then again passes over rollers or sprockets 2 through a second series of tanks D, E and G respectively, in which it is developed, fixed and finally washed. It passes thence through a drying cabinet H and to a final windup reel 0. As it enters the developing tank,'it passes an exposure station I, at which it is exposed to light controlled as in the manner fully shown and described in the Patent No. 1,690,616, as by anadiustable diaphragm having a control 0. There is further placed at this station an adlustablewedge indicated at 0 which has areas of different colors or diiierent densities of the same color, by which the color or the printing light may be controlled.

By means oi this expedient, the characteristics and quality of the finally developed image may be carefully maintained at predetermined or desired standards.

Itistobeunderstood that theshowing herein is intended to be sumcient only to enable those skilled in the art to understand and practice the invention. The particular structures used are, of course, quite immaterial to the carrying out of the process and many types of known developing apparatus could be employed. 5

Having thus described my invention, what I claim as new and desire to be secured by Letters Patent oi the United States is:

1. In a process for making photographic images in a single photographic emulsion layer by a reversal process involving successively the making 0! an original image in said layer, the removal of that image and the formation oi! a second image by a second exposure in the same layer, the step of dyeing the layer immediately prior to the second exposure with a filter dye absorptive or blue light whereby the exposure throughout the layer is controlled.

2. In a process for making motion picture images on a photographic film band by a continuous reversal bath that comprises successively passing the film band comprising at each step the same layers through an image developing bath, a bleaching bath, a light exposure and a second developing bath, the step oi submitting the film band to a filter dye bath immediately before submitting it to the light exposure.

3. In a process i'ormaking motion picture images on a photographic film band carrying a photographic layer by a continuous reversal process that comprises passing the hand through stations at which successively silver images are formed in the layer, the silver images are removed, the band is submitted to a controlled exposure and images are formed in said layer, the steps of submitting the film immediately prior to the second exposure being dyed with a non-sensitizing dye which colors the layer yellow and, after the exposure, washing out the dye.

4. In a process for making motion picture images on a film band carrying a photographically sensitive silver halide emulsion by a continuous reversal process that comprises passing the band through stations that successively develop silver images in the emulsion, remove such images, subiectthe band to a controlled second exposure I thereby forming latent images in the emulsion and develop such images, the steps of submitting the film band to an aqueous dye bath which stains said emulsion immediately prior to the exposure and washing out the dye from said emulsion im-v mediately after the exposure; I

' mm C. D. HICKMAN 

